A new literary project, eccentric and entrancing, by writer Doug Dorst and J.J. Abrams (yes, that J.J. Abrams, creator of "Lost"), makes a case for spending the extra cash. Theirs is a celebration of the book as a physical thing, possessor of wonders that cannot be translated into digital bits.

Ironically, "S." isn't even a book. It's hard to say exactly what it is. A literary experiment? A work of art? Whatever it is, the thing arrives shrink-wrapped in plastic, a cardboard sleeve containing a book that appears lifted off the shelves of a library. The book is "Ship of Theseus" by a writer named V.M. Straka, and it looks old. Its cover is battered, its pages are yellowed and stained, a library sticker is glued to its spine. Inside its back cover are "RETURN ON OR BEFORE" and "received" date stamps, along with a stamp admonishing borrowers to "KEEP THIS BOOK CLEAN."

The book is anything but. It is gloriously embroidered with marginalia and jammed with artifacts inserted between its pages. Footnotes throughout appear to be telling a story of their own, in code. Books, Dorst and Abrams seem to be saying, can be so much more than the words on a page. They can be physical expressions of time, of the lives of their readers. They can tell their own tales.

And so "S." really contains three stories running at once. There's Straka's "Ship of Theseus," the story of an amnesiac, known only by the initial S., shanghaied into a nightmarish adventure. But then there's the mystery surrounding Straka's identity. Nobody knows exactly who he was, despite his fame and notoriety as a political agitator. All of this is explained to us in the Translator's Note and Foreword by the translator, "F.X. Caldeira," whose identity also is in question and who seems to be writing to Straka in code in the book's footnotes.

We know this thanks to Jen and Eric, Straka obsessives who correspond with each other in the book's margins. They meet in the margins after Jen, an undergraduate working in a university library, finds Eric's commentary penciled into the book. In her neat cursive penmanship, Jen cheerfully reaches out: "Hey — I found your stuff while I was shelving. (Looks like you left in a hurry!) I read a few chapters + loved it … -Jen."

Eric writes back, and so begins a friendship, a romance and a shared mania for all things Straka. Jen's cursive and Eric's block letters fill the book's margins, providing commentary on the book as they fall for each other and work on the mystery of Straka's identity.

There also are almost two dozen trinkets inserted between the book's pages, including postcards, letters and a map drawn in ink on a paper napkin. There's a navigational wheel that's also a decoder. (This is J.J. Abrams, after all, so of course there are codes, a secret society, strange goings-on with time and obsessive fans poring over all of it.)

The three stories mirror each other throughout. Often, some phrase in the text will prompt Eric or Jen to talk about a moment in life or tell a story or ask a question. Books are a conversation between reader and author, and in a physical book, sometimes evidence of that conversation is left behind.

Here, in "Ship of Theseus," a character named Stenfalk describes an old book that proves critical to amnesiac S. and to Eric and Jen:

"A big, dusty old thing. Passed down in my family for generations. When he opened it, you could smell the musty pages from across the room — but it was full of the most wonderful stories."

Jen has underlined the passage about the "musty pages" and, off to the side, written in her neat cursive, "I've always loved this smell." Eric responds, "Me, too. Love how strong it is in the south stacks."

In the book, S. asks Stenfalk whether his family still has the book. "'No,' Stenfalk says. 'It was stolen. As most beautiful things eventually are.'"

Eric has underlined that passage and written a sour little note about it, prompting a question in the margins from Jen. He reveals that he wrote that note right before he was hospitalized for mental-health issues.

Isn't this the pleasure of reading? Dorst and Abrams are saying that books are a way to talk about life, to think about life. They are a way to reach out to each other, to talk about hard things through the intermediary of an author's words.

The interplay among the three stories makes reading "S." a bit of a challenge. It is slow going. It is a puzzle, with multiple mysteries to be solved: Who is S., and what happened to him before he had amnesia? Who is Straka, and what happened to him? Will Eric and Jen solve the mystery of Straka, and will they ever meet in person?

And yet, reading "S." is fun, and the book feels alive in ways that a digital version would not. Which is more intriguing — an e-book or, as described in "Ship of Theseus," "a thick tome bound in brown leather that is cracked and covered with dark, oily stains"? Who wouldn't pick the thick tome?

It turns out that "Sycamore Row" also is available used, in good condition, for $14.48 on Amazon. The seller warns that the book may suffer "some shelf wear" and "may contain highlighting/notes."